Effects of Punch Geometry on Formability and Forming Load

2021 ◽  
Vol 62 (726) ◽  
pp. 87-94
Author(s):  
Nasa KAWAGOSHI ◽  
Shohei TAMURA ◽  
Takeshi KAWACHI
Keyword(s):  
2007 ◽  
Vol 340-341 ◽  
pp. 649-654 ◽  
Author(s):  
Jung Min Seo ◽  
Dong Hwan Jang ◽  
K.H. Min ◽  
H.S. Koo ◽  
S.H. Kim ◽  
...  

Combined extrusion processes generally have advantages of forming in terms of the minimum deformation power since the material is pressed through two or more orifices simultaneously. This paper is concerned with the analysis of forming load characteristics of a forward-backward can extrusion process using thick-walled pipe as an initial billet. The combined tube extrusion process was analyzed by using a commercial finite element code. A thick-walled pipe was selected as an initial billet and the punch geometry has been chosen on the basis of ICFG recommendation. Several tool and process parameters were employed in this analysis and they are punch nose radius, backward tube thickness, punch face angle, and frictional conditions, respectively. The main purpose of this study is to investigate the effect of process parameters on the force requirements in combined extrusion process. The possible extrusion process to form a forward-backward tube parts in different process sequences were also simulated to investigate the force requirements in sequential operations, i.e. separate operations. It was easily concluded from the simulation results that lower forming load was predicted for the combined extrusion, compared to those for separate sequential operations. It was also revealed that the punch nose radius and the punch face angle have little effect on the force requirements and the forming load increases significantly as the frictional condition along tool-workpiece interface becomes severe. The simulation results in this study suggest that the combined extrusion process has strong advantage in terms of force requirements as long as the simultaneous material flow into multiple orifices could be closely controlled.


2006 ◽  
Vol 519-521 ◽  
pp. 919-924 ◽  
Author(s):  
B.S. Ham ◽  
J.H. Ok ◽  
Jung Min Seo ◽  
Beong Bok Hwang ◽  
K.H. Min ◽  
...  

This paper is concerned with forward rod extrusion combined simultaneously with backward tube extrusion process in both steady and transient states. The analysis has been conducted in numerical manner by employing a rigid-plastic finite element method. AA 2024 aluminum alloy was selected as a model material for analysis. Among many process parameters, major design factors chosen for analysis include frictional condition, thickness of tube in backward direction, punch corner radius, and die corner radius. The main goal of this study is to investigate the material flow characteristics in combined extrusion process, i.e. forward rod extrusion combined simultaneously with backward tube extrusion process. Simulation results have been summarized in term of relationships between process parameters and extruded length and volume ratios, and between process parameters and force requirements, respectively. The extruded length ratio is defined as the ratio of tube length extruded in backward direction to rod length extruded in forward direction, and the volume ratio as that of extruded volume in backward direction to that in forward direction, respectively. It has been revealed from the simulation results that material flow into both backward and forward directions are mostly influenced by the backward tube thickness, and other process parameters such as die corner radius etc. have little influence on the volume ratio particularly in steady state of combined extrusion process. The pressure distributions along the tool-workpiece interface have been also analyzed such that the pressure exerted on die is not so significant in this particular process such as combined operation process. Comparisons between multi-stage forming process in sequence operation and one stage combined operation have been also made in terms of forming load and pressure exerted on die. The simulation results shows that the combined extrusion process has the greatest advantage of lower forming load comparing to that in sequence operation.


2013 ◽  
Vol 712-715 ◽  
pp. 627-632
Author(s):  
Min Liu ◽  
Qing Xian Ma

Aiming at the disadvantages of low utilization ratio of steel ingot, uneven microstructure properties and long production period in the solid steel ingot forging process of heavy cylinder forgings such as reactor pressure vessel, a new shortened process using hollow steel ingot was proposed. By means of modeling of lead sample and DEFORM-3D numerical simulation, the deformation law and grain refinement behavior for 162 ton hollow steel ingot upsetting at different reduction ratios, pressing speeds and friction factors were investigated, and the formation rule of inner-wall defects in upsetting of hollow steel ingots with different shape factors was further analyzed. Simulation results show that the severest deformation occurs in the shear zone of meridian plane in the upsetting process of hollow steel ingot, and the average grain size in the shear zone is the smallest. As pressing speed increases, the forming load gradually increases and the deformation uniformity gets worse, while the average grain size decreases. An increase in friction factor can increase the peak value of effective strain, but it significantly reduces the deformation uniformity, increases the forming load and goes against grain refinement. Moreover, the four kinds of defects on the inner wall of steel ingot can be eliminated effectively by referring to the plotted defect control curve for hollow steel ingot during high temperature upsetting.


2006 ◽  
Vol 519-521 ◽  
pp. 949-954 ◽  
Author(s):  
Beong Bok Hwang ◽  
J.H. Shim ◽  
Jung Min Seo ◽  
H.S. Koo ◽  
J.H. Ok ◽  
...  

This paper is concerned with the analysis of the forming load characteristics of a forward-backward can extrusion in both combined and sequence operation. A commercially available finite element program, which is coded in the rigid-plastic finite element method, has been employed to investigate the forming load characteristics. AA 2024 aluminum alloy is selected as a model material. The analysis in the present study is extended to the selection of press frame capacity for producing efficiently final product at low cost. The possible extrusion processes to shape a forward-backward can component with different outer diameters are categorized to estimate quantitatively the force requirement for forming forward-backward can part, forming energy, and maximum pressure exerted on the die-material interfaces, respectively. The categorized processes are composed of combined and/or some basic extrusion processes such as sequence operation. Based on the simulation results about forming load characteristics, the frame capacity of a mechanical press of crank-drive type suitable for a selected process could be determined along with securing the load capacity and with considering productivity. In addition, it is suggested that different load capacities be selected for different dimensions of a part such as wall thickness in forward direction and etc. It is concluded quantitatively from the simulation results that the combined operation is superior to sequence operation in terms of relatively low forming load and thus it leads to low cost for forming equipments. However, it is also known from the simulation results that the precise control of dimensional accuracy is not so easy in combined operation. The results in this paper could be a good reference for analysis of forming process for complex parts and selection of proper frame capacity of a mechanical press to achieve low production cost and thus high productivity.


2013 ◽  
Vol 683 ◽  
pp. 552-555
Author(s):  
Lu Li ◽  
Fang Wang

A crankshaft pre-forging with the resistance wall structural die is analyzed by the finite element method. The influence of forming velocity on the filling capacity, the maximum forming load, die surface temperature and wear depth is discussed. The results show that the values of the maximum forming load, die surface temperature and wear depth increase, while the minimum unfilled distance decreases as the forming velocity increases. It is found that increasing the value of forming velocity is benefit for improving the filling capacity. However, excessive forming velocity increasement may results in poor service life of tools. When die wear, production efficiency and cost be considered, it is indicated that the range of the forming velocity is 10-100 mm/s, the process has the optimal service performance. The analysis and conclusions in this paper are helpful in developing the technology specification of newly developed resistance wall structural die.


2011 ◽  
Vol 473 ◽  
pp. 251-258 ◽  
Author(s):  
Sam Coppieters ◽  
Pascal Lava ◽  
Hugo Sol ◽  
Paul van Houtte ◽  
Dimitri Debruyne

Clinching is a mechanical joining technique which involves severe local plastic deformation of two or more sheet metal parts resulting in a permanent mechanical interlock or joint. The required forming load and energy can be determined with the aid of the finite element method. However, a good knowledge of the elasto-plastic properties is of utmost importance to perform a sufficiently accurate simulation. This paper presents two alternative material tests to identify the hardening behaviour of sheet metal beyond the point of maximum uniform elongation. In addition, the material tests were applied to DC05 and the identified material behaviour is evaluated through the prediction of the forming load during clinching.


2021 ◽  
Author(s):  
Zuofa Liu ◽  
Xi Wang ◽  
Wenjie Feng ◽  
Jie Zhou ◽  
Zhiyuan Qu ◽  
...  

Abstract Due to the complex metal flow in the cold extrusion of sun gear, the teeth accuracy of formed sun gear is poor. In order to improve the accuracy of the extruded sun gear, a novel precision finishing method with different tools was proposed in this study. Finite element simulations were performed using DEFORM, and a new finite element (FE) prediction strategy was developed to obtain an in-depth understanding of the deviation distribution laws of the finished sun gear. Then, the influences of different finishing tools on tooth deformation, tool stress, forming load and tooth accuracy were examined. The investigation results show that the profile accuracy of external gear can be improved from ninth to seventh class, lead accuracy can be enhanced from tenth to eighth class, and total M value deviation of internal spline is reduced to 72.3 μm by the precision finishing method with interference mandrel. Therefore, the interference mandrel is recommended as the optimal reshaping tool for commercial production of sun gears. The simulation results are well agreed with the experimental results, which verifies the feasibility of the precision finishing method and the reliability of the FE prediction strategy.


Author(s):  
Beong Bok Hwang ◽  
J.H. Shim ◽  
Jung Min Seo ◽  
H.S. Koo ◽  
J.H. Ok ◽  
...  

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